Quick Answer
Area formulas: Rectangle = width × height · Circle = π × radius² · Triangle = ½ × base × height · Trapezoid = ½ × (side a + side b) × height. Results are shown in m², cm², and ft² simultaneously.
What Is Area?
An area calculator finds the two-dimensional space enclosed by a shape. Area is one of the most practically useful geometric measurements, from calculating how much paint, tile, or flooring a room needs, to working out plot sizes in real estate, to engineering and construction takeoffs.
Different shapes have fundamentally different area formulas, which is why a single calculator that handles rectangles, circles, triangles, and trapezoids in one place saves real time. Each formula comes from a distinct geometric principle: rectangles multiply two linear dimensions, circles use π to capture the curved boundary, triangles use the half-base-times-height relationship, and trapezoids average their two parallel sides before multiplying by the height.
This calculator works in meters by default, returning results in m², cm², and square feet, making it useful whether you're working with metric (most of the world, construction, science) or imperial (US, UK real estate) measurement systems.
How to Use
- 1Select the shape you want to calculate the area of.
- 2Enter the required dimensions, width and height for a rectangle, radius for a circle, base and height for a triangle, both parallel sides and height for a trapezoid.
- 3Area is calculated instantly in m², and also converted to cm² and ft².
Formula
Area = Width × HeightArea = π × Radius² (π ≈ 3.14159)Area = ½ × Base × HeightArea = ½ × (Side a + Side b) × HeightExample: Circle with radius 7 m
- Area = π × 7² = 3.14159 × 49
Tips & Things to Know
- The radius of a circle is half its diameter, if you measure across the middle (diameter), divide by 2 before entering it as the radius.
- For a triangle, the height must be the perpendicular height (a right-angle drop from the apex to the base), not the length of a slanted side.
- A trapezoid has two parallel sides, if only one pair of sides is parallel, it's a trapezoid; if both pairs are parallel, it's a parallelogram (which uses the same formula: base × height).
- Room area for flooring or painting: measure in meters, calculate in m², then add 10–15% for cuts and waste before purchasing materials.
- 1 m² = 10,000 cm² = 10.764 ft² = 1.196 yd²